Fuel injector for internal combustion engines



p 9, 1970 I M. J. BERLYN 3,531,052

FUEL INJECTOR FOR INTERNAL COMBUSTION ENG-INES Filed Feb. 19. 1968 2 Sheets Sheet l INVE'NTCK mARfrn/ 70ml BERLY BN 1 d Sept. 29, 1910 M. J. BERLYN 3,531,052

FUEL INJECTOR FOR INTERNAL COMBUSTION ENGINES Filed Feb. 19. 1968 2 Sheets-Sheet 2 5% 27 i 35 I 74 39 x g2 United States Patent 3,531,052 FUEL INJECTOR FOR INTERNAL COMBUSTION ENGINES Martin J. Berlyn, Leeds, England, assignor, by mesne assignments, to Clayton Dewandre Holdings Limited, London, England, a company of Great Britain Filed Feb. 19, 1968, Ser. No. 706,519 Int. Cl. Bb 1/30 US. Cl. 239-533 3 Claims ABSTRACT OF THE DISCLOSURE A fuel injector of the multiple orifice type is provided with means for creating rotary swirl of the fuel in the sac hole of the nozzle tip.

This invention relates to fuel injectors for diesel engines of the open-chamber direct-injection type and particularly to multiple-orifice type injectors, the object of the invention being the provision of an improved injector of this character giving better independent control of the spray characteristic and corresponding improved engine performance, without interfering with the valve settings and spray hole geometry.

According to the invention a multiple-orifice type fuel injector includes means for creating a rotary swirl of fuel in the sac hole of the nozzle tip.

Two methods of carrying out the invention will now be described with reference to the accompanying drawings, wherein FIG. 1 is a diametral section of an injector assembly according to a first embodiment,

FIG. 2 is a similar view of a second embodiment, and

FIG. 3 is a fragmentary transverse section on the line III-III of FIG. 2.

In the drawings the left hand half of the section shows the valve in the closed position and the right hand half shows the valve in the fully open position. The invention is shown applied to the fuel injector forming the subject of our co-pending application S.N. 679,687 filed Jan. 15, 1968 wherein an injector assembly is formed as a replaceable unit adapted to be clamped to a nozzle holder formed for mounting in the cylinder head of an engine.

As shown, the injector assembly of FIG. 1 comprises a body provided with an opening or port 11 for admission of fuel and an integral flange 12 by which it is clamped to the nozzle holder, a spring chamber 13, a counterbore '14 and a deformable skirt 15. A co-axial valve guide 16 is provided with a bore 17, a conical seat 18, an enlarged bore 19, a flange 20 having a face 21, and transverse ports 22. A spring 23 is held between a spring abutment 24 of valve guide 16 and a spring seat 25 which is retained on a valve member 26 by semicircular cotters 27 in groove 28 of valve member 26. The latter has a neck 29, of smaller diameter than valve stem 30, a conical face 31 and a piston 32 which is a fuel-throttling fit in the enlarged bore 19 of valve guide 16. A nozzle tip 33 is provided with a face 34, a shoulder 35, a sac hole 36 and spray orifices 37.

In assembly of the injector a subassembly is first made of valve member 26, guide 16, spring 23, spring seat 25, cotters 27 and valve lift adjustment shim 38 and this subassembly is inserted into body 10 until flange 20 of guide 16 is at the end of counterbore 14 of body 10. Nozzle tip 33 is then inserted into counterbore 14 of body 10 until face 34 of nozzle tip 33 abuts face 21 of flange ice 20 of guide 16 and deformable skirt 15 of body 10 is then folded over shoulder 35 of nozzle tip 33.

In operation of the injector, fuel from a pump is delivered through a duct of the nozzle holder and enters at opening 11, flowing through spring chamber 13 and by way of radial ports 22 into bore 17. Having forced valve 26 open by overcoming the valve-closing bias of spring 23, the fuel passes through enlarged bore 19 into sac hole 36 and through spray orifices 37.

If piston 32 is a fluid-throttling fit in enlarged bore 19, valve 26 reciprocates at high frequency during flow of fuel through the nozzle tip, this having a beneficial influence upon the dispersion of the spray from orifices 37 and results in improved combustion of the fuel.

In carrying out the present invention the piston 32 of valve 26 is provided with a conical fairing 39 extending downwardly into the nozzle tip, the piston and fairing being formed with helical or inclined peripheral grooves 40 which create a rotary swirl in the fuel flowing past these elements. In practice it is found that the rate of swirl increases as the fuel reaches the sac hole 36, due to the relatively small diameter of this hole, and results in the fuel issuing from the orifices 37 being broken up into particles of extremely small size.

FIGS. 2 and 3 illustrate an alternative method of creating a rotary swirl in the fuel flowing to the nozzle tip, this elfect being achieved in this instance by forming the transverse ports 22a in the valve guide 16 tangentially to the bore 17. The rotary action of the fuel about the axis of the nozzle tip thus produced has been found to persist in the fuel as it passes the piston 32 and fairing 39 into the nozzle tip. The inclusion of the conical fairing is not essential in either embodiment of the invention but its provision has been found to improve injector performance.

I claim:

1. A fuel injector of the multiple orifice type comprising a valve guide having in longitudinal sequence a first bore and a second larger bore aligned on an axis, a valve seat located longitudinally between said bores and a plurality of transverse ports leading through the valve guide to said first bore; a valve spring surrounding said guide; a valve member having a stem extending through and reciprocally guided by said first bore, said guide and said stem being so engaged by said spring that the valve member is biased by the spring to engage a portion thereof with said valve seat, a piston on said valve member at the throttling fit in said second larger bore; a nozzle tip in communication with and extending over the end of said second larger bore, said tip enclosing a space into which said piston is displaced by fluid fuel pressure in the fully open condition of said valve member, said tip being formed with a plurality of discharge openings communicating with said space and arranged at an angle to said axis; and means for creating a rotary swirl about said axis in fuel flowing to said nozzle tip, said swirl creating means comprising a plurality of inclined grooves in the periphery of said piston, said grooves being most effective in imparting swirl to the fuel when said valve member is partly open and least effective when the valve member ias fully open and said piston is displaced into said space.

2. A fuel injector as claimed in claim -1, in which said swirl-creating means comprises transverse ports in said guide intersecting and essentially tangential to said first bore.

3 4 3. The fuel injector defined in claim 1, wherein said 3,118,611 1/1964 Berlyn 239453 X valve spring is compressed between opposed flanges on 3,241,768 3/1966 Croft 239-453 X said guide and said valve member. FOREIGN PATENTS References Cited 5 827,877 2/1938 France. UNITED STATES PATENTS 2,433,985 1/1948 Fodor 239 600 X SAMUEL F. COLEMAN, Primary Examiner 2,860,780 11/1958 Ziesche et a1 239--533 

